Toxic effects of selected proprietary dry eye drops on Acanthamoeba

Abstract

Amoebae of the genus Acanthamoeba are ubiquitous protists that have been isolated from many sources such as soils, water and the air. They are responsible for infections including fatal encephalitis and a severe keratitis in humans. To date, there is no satisfactorily effective therapeutic agent against this pathogen and the infections it causes are exacerbated by the existence of a resistant cyst stage produced by this amoeba. As dry eye syndrome is a risk factor for Acanthamoeba keratitis, we aimed to evaluate the anti-Acanthamoeba activity of a variety of proprietary eye drops intended to treat dry eye syndrome. From the nine eye drop formulations tested, “Systane Ultra” was determined to be the most active against all tested Acanthamoeba strains. During our investigations into the mode of action of Systane Ultra, we discovered that it decreases mitochondrial membrane potential and ATP levels, induces chromatin condensation, and increases the permeability of the plasma-membrane.

Staurosporine from Streptomyces sanyensis activates Programmed Cell Death in Acanthamoeba via the mitochondrial pathway and presents low in vitro cytotoxicity levels in a macrophage cell line

“…Programmed Cell Death (PCD) has been previously reported in our laboratory in Acanthamoeba genus after incubation with compounds such as statins and voriconazole among other molecules 2,27,28 . The process of PCD involves multiple changes such as chromatin condensation, cell shrinkage and loss of mitochondrial potential among other phenomena 29 .…”

Laurinterol from Laurencia johnstonii eliminates Naegleria fowleri triggering PCD by inhibition of ATPases

“…The experiment was carried out by following the manufacturer's recommendations, and 5 × 10 5 cells/ml well were incubated in a 96-well plate for 24 h with the previously calculated IC 90 . As it has been previously reported 52 , the double-staining pattern allows the identification of three groups in a cellular population: live cells will show only a low level of fluorescence, cells undergoing PCD will show a higher level of blue fluorescence (as chromatin condenses), and dead cells will show low-blue and high-red fluorescence (as the Propidium Iodide stain enters the nucleus).…”

In Vitro Evaluation of Combined Commercialized Ophthalmic Solutions Against Acanthamoeba Strains

“…Both of these compounds have been reported to be effective against different bacteria species [18,19] and, on the other hand, propylene glycol also presents a remarkable preservative effect [20,21]. A previous study from our laboratory has shown the anti- Acanthamoeba activity of Systane ® Ultra and its induction of programmed cell death (PCD) mechanism [16]. In addition, the presence of a POLYQUAD ® , which has been demonstrated as capable to activate and elevate the secretion of inflammation markers, is a disadvantage in the ocular use of Systane ® Ultra.…”

“…The in vitro effect of Systane ® Ultra and Naviblef ® Daily Care against the three tested Acanthamoeba strains ( A. castellanii Neff, A. polyphaga (ATCC ® 30461™) and A. griffini ), was evaluated using a colorimetric assay based on the alamarBlue TM Cell Viability Reagent (Invitrogen by Thermo Fisher Scientific), as it has previously described [7,16,26,27]. As first step, the Acanthamoeba culture was seeded in triplicate on a 96-well microtiter plates (50μL from a stock solution of 5 × 10 4 cells/mL).…”

“…Systane ® Ultra (Systane ® ; Alcon, Fort Worth, TX, USA; Table 1) is one of the most widely used ocular lubricants in the USA [15]. In a recent study, the amoebicidal activity of this product was reported as well as its potential use for the prevention or even treatment of Acanthamoeba keratitis, or to contribute for an optimized solution [16]. Naviblef ® Daily Care (Novax ® Pharma, Monaco; Table 1) is a commercialized cleaning foam which contains tea tree oil (TTO) (0.02%) and chamomile oil (CO).…”